The provision of directors for antennas, especially VHF band antennas, have been well known for a number of years. A director has been generally defined as "a parasitic element located forward of the driven element of an antenna, intended to increase the directive gain of the antenna in the forward direction." IEEE Standard Dictionary of Electrical & Electronics Terms (1977). Typically, the directive gain of an antenna is dependent principally upon the size of the antenna, expressed in wavelengths. The larger the antenna, the greater is likely to be its gain.
In U.S. Pat. No. 2,700,105 issued to J. R. Winegard, the director element utilized inductance between its half sections to operate as a director in both the low and high VHF bands. This type of dual band director commonly appears on VHF antennas and, as set forth, in this patent, the director used a degree of inductive reactance at the high frequency end of the low VHF band to provide substantial directive gain even though the length of the elements would otherwise be too short at the high frequency end of that band to provide directional capabilities. This director utilized an inductive coupling unit interconnecting the half-sections of an element. Hence, the inboard ends of each half section were interconnected with the coupling element comprised as a folded, closed line in the low VHF band, while isolating the two half-sections in the high VHF band.